1. Field of the Invention
The present invention relates to an oil seal which is a kind of sealing device, particularly to an oil seal configured so as to improve the lubricant oil supplying performance to the seal lip sliding portion. The oil seal of the present invention is used in the technical fields relating to automobiles, or used in general-purpose machines or the like.
2. Description of the Conventional Art
For example, a well known conventional oil seal 51 is configured such that an annular installation section 52 fitted to a housing (not shown) and a seal lip 53 provided slidably and in closely contact with the circumference of a shaft not shown inserted to an inner peripheral surface of a shaft hole of the housing are integrally formed, as shown in FIG. 22. In such oil seal 51, supply of lubricant oil to the sliding portion 54 of the seal lip 53 is required to improve durability of the seal lip 53 which is made of a predetermined rubber-like elastic body to reduce an amount of wear due to sliding movement thereof. However, in the case that oil as an object to be sealed exists in a misty state for example, the lubricating property of sliding portion of the seal lip is tend to be poor, causing early abrasion and heat generation or the like. As a result, there is the problem that life time of the seal is remarkably shortened.
The conventional art is disclosed in Japanese unexamined patent publication No. 2005-282841 and Japanese unexamined patent publication No. 2003-056718.